1. Field of the Invention
This invention relates to a method for reducing brake wear of carbon brakes for aircraft, and more particularly relates to a method for reducing brake wear of aircraft carbon brakes by maintaining a light residual clamping force of the carbon brakes when braking is no longer commanded, to prevent release of the carbon brakes, without otherwise affecting normal braking.
2. General Background and State of the Art
Commercial aircraft commonly have landing gear with carbon brakes for wheels mounted to the wing and body of the aircraft. The carbon brakes typically include a torque plate and a carbon heat sink stack containing the friction surfaces that are clamped together with a clamping brake force to cause a wheel to decrease its speed of rotation. In such a conventional airplane carbon brake system, when braking is commanded, either by a pilot's actuation of a brake pedal or automatic braking, it causes the friction surfaces of the carbon brakes to make contact, creating brake torque to slow down the rotational speed of the wheel, and through contact with the ground, the taxi speed of airplane. When a release of braking is commanded, such as when the pilot discontinues the brake pedal command, the brake friction surfaces move apart and a layer of carbon falls away. The amount of wear of airplane carbon brakes is thus directly influenced by the number of brake applications, and is not significantly affected by the level of braking effort or intensity during braking. A gradual and small braking stop will cause approximately as much carbon brake wear as a sudden hard stop.
One conventional technique that was developed for reducing wear of an airplane having multiple wheels with carbon brakes, known as brake disabling, selective operation, or as taxi-brake select, involves the application of less than the total number of available brakes during taxiing of the airplane, and consequently the selective disabling of some of the brakes during taxiing. In this technique, different selections of brakes may be disabled for different stages of taxiing and for specific aircraft conditions. However, in order to control taxi speed and turning of an airplane multiple brake applications or “snubs” of low brake intensity still may be required, so that it would be desirable to provide a method of reducing the number of releases of aircraft carbon brakes once the aircraft carbon brakes have been applied when an airplane is taxiing, in order to reduce brake wear. The present invention satisfies this and other needs.